The officer who killed Brown said he had no choice

ABC - Ferguson, Missouri police officer Darren Wilson discussed his account of the moment he shot and killed black teenager Michael Brown in an exclusive interview with ABC News.

Speaking to ABC News' George Stephanopoulos Wilson, said Brown was charging at him, disregarding the officer's instructions.

"I started backpedaling, 'cause he's just getting too close and he's not stopping," Wilson said.

"After I fired the second round of shots, he gets about eight to 10 feet [away]. And as he does that, he kinda starts to lean forward like he's gonna tackle me. And eight to 10 feet is close and what I saw was his head. If he's gonna tackle me, he's gonna tackle me at that point. And I looked down my barrel of my gun and I fired."

The Aug. 9 shooting sparked months of protests, drawing national attention to the St. Louis suburb.

Wilson said he was driving to get lunch by himself - just a normal day, he says - when he encountered Brown and a friend walking in the middle of the street, "single-file on the double-yellow line." Wilson says he instructed the pair to walk on the sidewalk.

The first person, Brown's friend, Dorian Johnson, ignored Wilson, the officer said.

"And then Michael Brown came next and he had to exchange some explicit words with me," Wilson said. "He had said, "F*** what you have to say."

"First words to you?" Stephanopoulos asked.

"Yeah," Wilson responded.

At that point, Wilson says he noticed cigarillos in Brown's hand, noting that Brown and Johnson matched the description, he says, of suspects in the theft of cigars from a nearby convenience store earlier that day. Wilson said he wasn't sure if Brown was armed.

"I got on the radio and I asked for assistance," Wilson said.

Wilson said he parked and tried to get out of his vehicle, when Brown again cursed at the officer and slammed the officer's car door.

"I ... again taken aback because I've never been trapped in my car," Wilson told Stephanopoulos. "I use my door to try and push him back and yell at him to get back. And again he just pushed the door shut and just stared at me."

"So you're staring each other down?" Stephanopoulos asked.

"Yeah, he stared at me, like almost over top of me ... looked like he was trying to intimidate me. And as I looked back at him, all of a sudden punches started flying ... He threw the first one and hit me in the left side of my face," Wilson said.

Wilson said he doesn't believe he could have done anything differently that day - and says he has a clean conscience.

"The reason I have a clean conscience is 'cause I know I did my job right," he said.

Following Monday's announcement that a grand jury declined to bring charges against Wilson, Brown's relatives released a statement, saying "We are profoundly disappointed that the killer of our child will not face the consequences of his actions."

Wilson said he feels remorse about the outcome of the altercation.

"I think those are grieving parents who are mourning the loss of their son," Wilson said.

"Nothing you could say, but, again, you know, I'm sorry that their son lost his life. It wasn't the intention of that day. It's what occurred that day. And there's no ... nothing you could say that's gonna make a parent feel better."